In particular, primordial black holes (PBHs), originally proposed as dark matter particle candidates (e.g., [1]}), are now becoming popular as possible early BH seeds Dark matter PBHs are predicted to emerge from large primordial density fluctuations (the same overdensities that lead to the formation of galaxies) collapsing onto themselves soon after the Big Bang, probably before recombination, during the radiation dominated era (see, e.g., the review by [2]}) and are expected to cover a wide mass range, from \(10^{-10} M_\odot \)  up to \(10^{7} M_\odot \)  [3]}.
